A minecart was left running on a helical track with powered sections which goes up about 4 levels and then back down in a continuous loop.
On one occasion on returning to the site the minecart was found to be travelling one block down from the track locations.
Observed only once.
Is this still an issue in the most recent versions (currently that is 1.10.2, or 16w42a) of Minecraft? If so, please update the affected versions and help us keeping this ticket updated from time to time.